The extraction of heavy oil and/or bitumen from an underground hydrocarbon reservoir via the pumping of viscous hydrocarbon-containing mixtures to surface presents significant problems with respect to the erosion of mechanical equipment (such as the pumps) which are used to pump such viscous mixtures to surface.
The cause of the erosion is due largely in part to the high abrasiveness of the viscous pumped substance, and the presence of solid particles in the mixture, such as sand, silicates, and tailings.
In making its way through the pump mechanism, the viscous fluid particularly causes erosion of the impeller blades, which ultimately leads to wear and loss of performance, and indeed subsequent inoperability of the pump. The result of the ongoing wear on the apparatus causes significant downtime for repairs and replacements, increasing inefficiencies and ultimately increasing maintenance costs and pump failures.
Pump apparatus with impeller blades used in the handling of viscous fluids are found in the prior art, such as those disclosed in Canadian Patents 2,543,970, 2,185,176, 2,229,018 and 2,235,045.
Canadian Patent 2,543,970 teaches a centrifugal pump, having a wear plate coupled with a centrifugal pump and impeller apparatus. Wear plates add additional cost, and may in some cases reduce performance.
CA 2,185,176 discloses a pump/separator apparatus that utilizes an inner impeller with a stack of radially and concentrically extending circular disks.
Likewise, CA 2,229,018 discloses a pump/separator apparatus with impellers mounted within a cylindrical housing. The impellers found in CA 2,185,176 are in a diverging upwardly external shape. In CA 2,185,176 there are also internal pumping components located at each stack.
CA 2,235,045 teaches an impeller assembly with asymmetric concave blades.
However, there exists a real need in the industry for an pump apparatus that will provide substantial pressure and volumetric output, and be able to survive for an extended period of time without repair or replacement.